Glass melting treatment method

Abstract

PCT No. PCT/JP94/00377 Sec. 371 Date Feb. 23, 1995 Sec. 102(e) Date Feb. 23, 1995 PCT Filed Feb. 9, 1994An object material to be melted (radioactive liquid waste and glass material) 16 is charged into the interior of a cold-crucible induction melting apparatus 10, and a conductor 18 the melting point of which is higher than that of the glass material is inserted into a melting furnace 12. A high-frequency current is supplied to a coil 14 so as to generate heat in the conductor and indirectly heat the glass material. The conductor is withdrawn after a part of the glass material has been put in a molten state. The glass material as a whole is thereafter kept in a molten state while maintaining the induction heating by the molten glass material. The conductor inserted into the melting furnace is, for example, a silicon carbide rod. The surface of the molten material which contacts the inner surface of the melting furnace turns into a solid layer (skull) due to cooling, so that the molten material does not directly contact the refractories. This enables the high-temperature corrosion of the melting furnace to be prevented.

We claim: 
     
       1. A glass melting method for use in vitrification of radioactive liquid waste, comprising the steps of: charging a radioactive liquid waste and a glass material into an interior of a melting furnace in a cold-crucible induction melting apparatus,   inserting a conductor having a melting point which is higher than that of said glass material into an interior of said melting furnace,   supplying a high-frequency current to a high-frequency coil disposed in said melting apparatus so as to generate heat in said conductor and to indirectly heat said glass material with the generated heat by induction heating,   withdrawing said conductor after a part of said glass material has been changed to a molten state, and thereafter   keeping said glass material as a whole in a molten state while maintaining the induction heating by said molten glass material.   
     
     
       2. A method according to claim 1, wherein said conductor inserted into the interior of said melting furnace is a silicon carbide rod.